A number of techniques are known for detecting areas of interest in an image, such as a face or other identified object of interest. Face detection is an area of particular interest, as face recognition has importance not only for image processing, but also for identification and security purposes, and for human-computer interface purposes. A human-computer interface not only identifies the location of a face, if a face is present, it may also identify the particular face, and may understand facial expressions and gestures.
Many studies on automatic face detection have been reported recently. References for example include “Face Detection and Rotations Estimation using Color Information,” the 5th IEEE International Workshop on Robot and Human Communication, 1996, pp 341-346, and “Face Detection from Color Images Using a Fuzzy Pattern Matching Method,” IEEE Transaction on Pattern Analysis and Machine Intelligence, vol. 21, no. 6, June 1999.
All the conventional methods of detecting human faces have their own advantages as well as shortcomings depending upon different algorithms used for processing images. Some methods are accurate but are complex and time-consuming.
Further, it is also very important to detect whether an image is a portrait. An image containing any human faces is called a portrait. In recent years, in association with the rapid spread of modern IT devices, a request for accurately determining a portrait has been increasing. For example, if the image can be judged as a portrait, the printer can adjust its parameters optimized for the portrait when it prints the image. Then the image's printing quality can be greatly improved. For this reason, there has been a strong demand for a device or a process, which can easily and automatically detect a portrait in an image.
Importantly, none of the conventional methods of detecting human faces saves the detecting result to the image, which makes it not convenient for further processing of the image if a particular process is needed for human face regions.
It is thus needed in the art to develop a method and apparatus that can identify human face regions within the image or determine whether an image is a portrait and save the result of the identifying process or the result of the determining process for further processing of the image.